The invention relates to an apparatus for producing reinforcing cages for rectangular pipes made of concrete. These reinforcing cages are required for large concrete pipes which have a rectangular or square cross section and of which the clear profile is, for example, in the order of magnitude of 2.times.4 m. The individual pipe sections are fitted together to give a pipeline or a through-channel and engage one inside the other in a positively locking manner by way of sockets or socket-like protrusions and recesses. The rectangular pipes are laid in the ground or covered with earth. In addition to water-engineering applications, these pipes can be used to produce, for example, pedestrian underpasses or passages under motorway embankments.
In the case of rectangular concrete pipes, in contrast to round concrete pipes, which have to be functional in every position, different wall regions are subjected to different degrees of loading. On account of the predominant bending loading, the top and bottom require considerably stronger steel reinforcement than the side walls. This means that the known wound reinforcing cages, which are dimensioned all the way round in accordance with the highest loading expected, are vastly over-dimensioned on the side walls. It is thus already known, in order to reduce the amount of steel used, for reinforcing cages to be configured individually over each surface area.
FIG. 1 shows a simplified illustration of a known rectangular concrete pipe and FIG. 2 shows a longitudinal section II--II through two concrete pipes which have been joined together, each concrete pipe containing an outer reinforcing cage 3 and an inner reinforcing cage 4. FIG. 3 shows a known reinforcing cage which is in the upright position and has longitudinal-wire sections 5 and a selection of different transverse-wire sections, it being possible to differentiate between rectilinear transverse-wire sections 6, transverse-wire angles 7 and transverse-wire brackets 8. The different static requirements which have to be met by the different reinforcing-cage surfaces can be satisfied in that a selection is made from the different transverse-wire sections, and in that these transverse-wire sections, in the case of relatively high stressing, are provided at smaller spacings apart in the longitudinal direction and/or larger wire cross sections are selected.